Endodontics · patient case question
The lateral radiolucency along the root of tooth 4 joining an apical lesion is most suggestive of:
Patient case: The tooth that bled during shaping
demo: 38-year-old male
chief: Referred for root canal treatment of a mandibular molar with a necrotic pulp.
history: Unremarkable. No allergies.
meds: None.
findings: Tooth 19 fails to respond to cold and is tender to percussion. Access is completed and the canals are irrigated. Partway through cleaning and shaping the patient reports sudden severe pain and the operator notices brisk bleeding from the canal along with rapid swelling of the cheek. Separately, tooth 4 in the same patient shows a narrow radiolucency running along the lateral root surface and joining an apical radiolucency.
Show answer and explanation
Correct answer: A. A vertical root fracture
- A. Correct. A vertical root fracture allows bacteria to colonise the fracture line, producing a J-shaped or halo radiolucency that runs along the lateral root surface and joins the apical lesion. A narrow deep isolated probing defect and a sinus tract near the gingival margin complete the picture, and the prognosis is extraction or root resection.
- B. A lateral periodontal cyst is a well-corticated round or teardrop radiolucency between the roots of vital teeth, most often mandibular premolars, and it does not connect to an apical lesion.
- C. External resorption produces a concavity or loss of root outline rather than a linear lucency tracking the length of the root.
- D. A periodontal abscess arises from an existing pocket, giving angular bone loss continuous with the crest rather than an isolated lateral lucency joining the apex.